Late binding of variables during test case generation for hardware and software design verification

Abstract

Methods and systems are provided that improve design verification by test generators by delaying assignment of values in the generated stimuli until these values are used in the design. Late binding allows the generator to have a more accurate view of the state of the design, and in order to choose correct values. Late binding can significantly improve test coverage with a reasonable performance penalty as measured by simulation time.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]This invention generally relates to design verification, and more specifically relates to test program generation in a context of a computer mechanism and methods for testing a design for compliance with the design specification.[0003]2. Description of the Related Art[0004]An important aspect of designing a hardware or software design, for example an advanced computer processor, is the ability to test the design of the processor thoroughly, in order to assure that the design complies with desired architectural, performance and design specifications. In current industrial practice, most of the verification is done by generating a very large number of tests by random test generators.[0005]Test program generators are basically sophisticated software engines, which are used to create numerous test cases. By appropriate configuration, it is possible for test generation to be focused on very specific ranges of conditions, or ...

AI Technical Summary

Benefits of technology

[0018]A test generator delays binding of values to variables during generation of test cases until these values are needed by the design. Each variable in the design is associated with a Boolean flag that indicates if the resource has a valid value, or has been evaluated such that its information content is known, or whether its information content is as yet undefined. Each such variable is associated with a linked list that points to other resources that should have the same value. Algorithms are presented, which enable the test generator to handle access to variables with the unidentified values, and deferring binding of the value until it becomes necessary. The technique is powerful enough to handle any arbitrary Boolean function. Experimentally, the late binding technique according to the invention improves the quality and rapidity of test coverage, with a reasonable performance penalty during simulation.

[0022]One aspect of the method includes designating a second unidentified resource for accommodation of a second signal that is a second input of the Boolean function, wherein an output of the Boolean function is insensitive to the second input, and avoiding binding the second unidentified resource with the second signal during execution of the test case.

Problems solved by technology

One problem with the approach of dynamic generation is that in many cases, by the time the generated inputs progress to the area of interest, the state of the design has changed, and the reason that led to the generation of the inputs no longer exists.

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